(50+51+52.+99+100)-(1+2+3.+59+58)
问题描述:
(50+51+52.+99+100)-(1+2+3.+59+58)
答
(50+100)×51÷2-(1+58)×58÷2
=3825-1711
=2114(50+51+52.......+99+100)-(1+2+3.......+49+48)=